San Antonio Mayor Julián Castro announced he’ll be seeking a third term leading city hall, and just like his keynote at the DNC, Castro was introduced by his twin brother, Congressman Joaquín Castro.

“You know, over the last four years I have watched my brother do every single thing that he can to make San Antonio the greatest American city we can possibly be," said Joaquín. "Whether it’s confronting our challenges to bringing more jobs to San Antonio, education – with Pre-K 4 SA, healthcare with combating childhood obesity.”

With his family and friends looking on, Castro told supporters at a rally on Saturday he wants to be the first mayor to take advantage of the relaxed term limits that allow him to seek up to four consecutive 2-year terms.

"And from the bottom of my heart, as someone who was born here and grew up here, I also knew that from the very beginning that we had to focus on two things: We had to continue to make the investments in infrastructure and in things that are so important to the success of a community -- our roads, our river, our buildings, our airport -- but we also had to do something that only in public service does the benefit of time allow, which is to not only to focus that which we can touch, but also to focus on a longer term vision," said Castro.

This means Castro could be mayor till 2017, and he told the gathering that he wasn’t planning on seeking higher elected office for a while, despite his growing national stature.

“So for those of you who are wondering, I’m not going anywhere. I love our city. I’m committed to making it a better place," Castro said.

Castro's next term will continue to build on projects already in the works, like implementation of Pre-K 4 SA and the redevelopment of downtown. He said the revitalization of Hemisfair would be his next major initiative.

Castro was first elected in 2009, and two years ago during his first re-election campaign he won with about 80 percent of the vote. There’s no serious challenge thus far for Castro but he joked that he would be happy just getting over 50 percent of the vote.